Memory Errors
Memory errors on the system display the new ON-FLASH-FLASH or ON-FLASH-ON failure code. If all memory fails, the LCD does not
turn on. Troubleshoot for possible memory failure by trying known good memory modules in the memory connectors on the bottom of the
system or under the keyboard, as in some portable systems.
NOTE:
The DDR4 memory is imbedded in board and not a replaceable DIMM as shown and referred.
USB features
Universal Serial Bus, or USB, was introduced in 1996. It dramatically simplified the connection between host computers and peripheral
devices like mice, keyboards, external drivers, and printers.
Table 3. USB evolution
Type
Data Transfer Rate
Category
Introduction Year
USB 2.0
480 Mbps
High Speed
2000
USB 3.0/USB 3.1 Gen 1
Port
5 Gbps
SuperSpeed
2010
USB 3.1 Gen 2
10 Gbps
SuperSpeed
2013
USB 3.0/USB 3.1 Gen 1 (SuperSpeed USB)
For years, the USB 2.0 has been firmly entrenched as the de facto interface standard in the PC world with about 6 billion devices sold, and
yet the need for more speed grows by ever faster computing hardware and ever greater bandwidth demands. The USB 3.0/USB 3.1 Gen 1
finally has the answer to the consumers' demands with a theoretically 10 times faster than its predecessor. In a nutshell, USB 3.1 Gen 1
features are as follows:
•
Higher transfer rates (up to 5 Gbps)
•
Increased maximum bus power and increased device current draw to better accommodate power-hungry devices
•
New power management features
•
Full-duplex data transfers and support for new transfer types
•
Backward USB 2.0 compatibility
•
New connectors and cable
The topics below cover some of the most commonly asked questions regarding USB 3.0/USB 3.1 Gen 1.
Speed
Currently, there are 3 speed modes defined by the latest USB 3.0/USB 3.1 Gen 1 specification. They are Super-Speed, Hi-Speed and Full-
Speed. The new SuperSpeed mode has a transfer rate of 4.8 Gbps. While the specification retains Hi-Speed, and Full-Speed USB mode,
commonly known as USB 2.0 and 1.1 respectively, the slower modes still operate at 480 Mbps and 12 Mbps respectively and are kept to
maintain backward compatibility.
USB 3.0/USB 3.1 Gen 1 achieves the much higher performance by the technical changes below:
•
An additional physical bus that is added in parallel with the existing USB 2.0 bus (refer to the picture below).
•
USB 2.0 previously had four wires (power, ground, and a pair for differential data); USB 3.0/USB 3.1 Gen 1 adds four more for two
pairs of differential signals (receive and transmit) for a combined total of eight connections in the connectors and cabling.
•
USB 3.0/USB 3.1 Gen 1 utilizes the bidirectional data interface, rather than USB 2.0's half-duplex arrangement. This gives a 10-fold
increase in theoretical bandwidth.
10
Technology and components
